Disposable dental appliance and method for preparing and placing silver amalgam fillings

ABSTRACT

A dental hand piece for mixing silver alloy and mercury to provide an amalgam for tooth fillings, extruding and carrying the amalgam into the tooth cavity and packing the amalgam in the cavity through the use of a single tool. The hand piece is disposable and is preloaded with measured proportions of the silver alloy and mercury which are stored in separate compartments until mixing thereof is desired to provide the amalgam. The tool is adapted for operation by the dentist&#39;&#39;s Doriot type straight hand piece, or the like, and automatically mixes the amalgam, extrudes the amalgam from the carrier portion thereof for deposit directly into the tooth cavity, and selectively packs the amalgam in the cavity upon response to actuation of the tamper mechanism by the dentist.

United States Patent Warden et al.

[54] DISPOSABLE DENTAL APPLIANCE AND METHOD FOR PREPARING AND PLACING SILVER AMALGAM FILLINGS [76] Inventors: Fuller Warden; Eugene W. Lewis; Bernard F. McNickle; Jack H. Mills, aT )T4 6 O4 with llarvard, Tulsa, Okla. 74135 [22] Filed: March 11, 1970 [21] Appl. No.: 18,452

[52] US. Cl. ..32/60 [51] Int. Cl ..A6lc 5/04 [58] Field of Search ..32/60 [56] References Cited UNlTED STATES PATENTS 3,552,023 l/l97l Osbeck ..32/60 3,280,459 9/1966 Walker et a1. ..32/60 3,411,213 11/1968 Spinello ..32/60 [151 3,715,806 [451 Feb. f3 1973 3,521,356 7/1970 Newman ..32/6O Primary Examiner-Robert Peshock AttorneyWil1iam S. Dorman 7] ABSTRACT A dental hand piece for mixing silver alloy and mercury to provide an amalgam for tooth fillings, extruding and carrying the amalgam into the tooth cavity and packing the amalgam in the cavity through the use of a single tool. The hand piece is disposable and is preloaded with measured proportions of the silver alloy and mercury which are stored in separate compartments until mixing thereof is desired to provide the amalgam. The tool is adapted for operation by the dentists Doriot type straight hand piece, or the like, and automatically mixes the amalgam, extrudes the amalgam from the carrier portion thereof for deposit directly into the tooth cavity, and selectively packs the amalgam in the cavity upon response to actuation of the tamper mechanism by the dentist.

5 Claims, 5 Drawing Figures PATENTED FEB 13 I975 Fig. 4'

Fig. 5

26 46 Fig. I

, INVENTORS FULLER WARDEN EUGENE W. LEWIS BERNARDE McNICKLE JACK H. MILLS DISPOSABLE DENTAL APPLIANCE AND METHOD FOR PREPARING AND PLACING SILVER AMALGAM FILLINGS This invention relates to improvements in method and means for the manipulating of silver amalgam in dentistry, and more particularly, but not by way of limitation, to a single tool for preparing, mixing, and extruding a silver amalgam for deposit directly into a tooth cavity, and packing of the amalgam within the cavity. 7

Silver amalgam is a common material used by dentists to place silver fillings in tooth cavities. Silver amalgam is an alloy of mercury with silver and other metals. The method most commonly in use today for preparing and placing silver amalgam fillings in tooth cavities involves complex, multitudinous and time consuming steps as follows:

1. A dispensing device is manually operated, usually by a dental assistant, to dispense a preselected or controlled quantity of silver alloy power and mercury into a mixing capsule. The mixing capsule normally contains a free moving metallic or plastic cylinder or pestle within its confines to aid in the amalgamation or trimration of the powder and mercury by agitation.

2. The loaded mixing capsule is placed in a suitable amalgamating device which is usually an electrically powered agitating mixer. The amalgamating devices normally amalgamate the silver powder and mercury ingredients in a time period of from 10 to 30 seconds.

3. The pestle is then removed from the mixing capsule and the mixture in the capsule is returned to the amalgamator for additional mulling.

4. The mixture is subsequently removed from the mixing capsule and placed in a squeeze cloth, with care being taken not to contaminate the mixed amalgam with moisture, such as perspiration of the hands and fingers of the user.

5. The mixture is then squeezed in the squeeze cloth to eliminate excess mercury therefrom.

6. The dental assistant, continuing the preparation of the amalgam, picks up a small portion of the readied mixture by loading the amalgam in the nozzle end of a suitable amalgam carrying instrument.

7. The loaded amalgam carrying instrument is passed by hand from the dental assistant to the dentist.

8. The nozzle end of the carrying instrument is placed in a tooth cavity and a load of the amalgam is ejected into the cavity through manual pressure applied by the dentist to the plunger of the carrying instrument.

9. The load of amalgam thus deposited in the tooth cavity is packed or condensed into the tooth cavity by the dentist through the use of one of several different types of plugging instruments. These may be hand pluggers, or air or electrically driven, and mechanical, pneumatic or ultrasonic in operation.

10. Simultaneously with the dentist's packing operation, the emptied carrying instrument is handed back to the dental assistant by the dentist in order that the dental assistant may reload the carrying instrument with amalgam.

1 l. The carrying instrument is reloaded as hereinbefore set forth and hand passed back to the dentist by the dental assistant, and the ejecting and packing steps are repeated.

12. This procedure of manual exchanges of the carrying instrument is repeated until the tooth cavity is adequately filled with silver amalgam. The filling is then trimmed of excess amalgam and carved to the proper contour.

13. The dental assistant must clean the mixing capsule, the pluggers and the carrying instruments thoroughly in order to remove any amalgam which may be set or adhered thereon so that there will be no amalgam residue to clog and freeze any of the working parts of the instruments. i

14. The instruments must then be sterilized in order that they may be used with the next patient needing this type of tooth filling.

The present invention contemplates a novel method and means for performing the entire operation from mixing of the amalgam to the filling of the tooth cavity with a single instrument or tool. The novel instrument is a disposable appliance particularly designed and constructed to introduce a revolutionary concept of manipulating silver amalgam for dentists use. The novel device combines the dispensing, amalgamation, carrying and packing steps of the present day method in one device in a simpler more coordinated operation. Further, the present invention contemplates a novel method of preparing, mixing and placing a silver amalgam filling in a tooth cavity in a manner which offers the dentist a substantial improvement over the present day method as follows: i

l. The novel appliance is a disposable dispenser, amalgamator, carrier and packer combined in one unit of simple design and economical construction.

2. The novel device is pre-loaded with the ingredients for silver amalgam in the proper portions, with the ingredients retained in separate compartments prior to mixing thereof.

3. The novel instrument is particularly designed and constructed as a disposable unit to be discarded upon dispensing of the contents thereof.

The device quickly mixes the silver amalgam ingredients quickly and thoroughly in a centrifuge type action rather than by agitation thus eliminating the need for agitating type amalgamators which are expensive.

5. The appliance contemplates the extruding of mixed silver amalgam from a nozzle type directly into a tooth cavity, thereby eliminating the need for amalgam carrying instruments which are used in the present day method of filling teeth with silver amalgam. This feature, of course, eliminates the numerous manual exchanges of the carrying instrument between the dentist and his assistant, and eliminates the need of refilling of, the carrying instrumentwith amalgam thus freeing the dental assistant for other important duties.

6. The novel tool is designed for use in the packing of the mixed silver amalgam filling material into a tooth cavity by a plugger point provided in the tool which is controlled by the dentist.

7. The plugger point in combination with the mixer apparatus assures the ejection of the mixed amalgam in an extrusion operation and in a manner for facilitating the condensing of the amalgam in the tooth cavity and for maintaining the amalgam fresh during the filling operation.

8. The novel tool may be utilized in the filling of substantially all of the teeth in the mouth, with the possible exception of approximately one to two per cent of cavities which may not be accessible.

9. The appliance may be adapted for use with a straight handpiece and easily and simply activated for placing and packing a silver amalgam filling in a tooth cavity with ease and may then be discarded in favor of another prefilled, disposable unit.

It is an important object of this invention to provide a novel method and means for the manipulation of silver. amalgam filling for tooth cavities.

Another object of this invention is to provide a novel method and means for completely preparing and placing a silver amalgam filling in a tooth cavity through the use of a single unit.

Still another object of this invention is to provide a novel method and means of preparing and placing a silver amalgam filling in a tooth cavity in a single, coordinated and simplified operation.

A further object of this invention is to provide a novel method and means of proportioning, amalgamating, carrying and placing and packing silver amalgam in a tooth cavity from within the confines of a single disposable appliance.

It is a further object of this invention to provide a novel method and means for filling a tooth cavity with silver amalgam wherein the multitudiness manual exchanges of hand tools between the dentist and dental assistant is eliminated, and the time and expense of placing the filling in the cavity is greatly reduced.

A still further object of this invention is to provide a -novel disposable appliance for completely preparing and placing a silver amalgam filling in a tooth cavity which is simple and efficient in operation and economical and durable in construction.

Still another object of this invention is to provide a novel disposable appliance which may be used with the usual Doriot type straight handpiece, or which may be designed .for operation by itsiown power source.

It is still another object of this invention to provide a novel disposable appliance which is preloaded with silver alloy powder and mercury maintained in separate compartments and which may be mixed as desired at the time of need for silver amalgam for filling a tooth cavity.

Other objects and advantageous features of the present invention will hereinafter more fully appear in connection with a detailed description of the drawings in which:

FIG. 1 is a sectional view partly in elevation of a dental appliance embodying the invention.

FIG. 2 is a sectional elevational view of the housing for a dental appliance embodying the invention.

FIG. 3 is a side elevational view of the mixing device and power shaft for a dental appliance embodying the invention.

FIG. 4 is a sectional elevational view of a retainer cup as utilized in a dental appliance embodying the invention.

FIG. 5 is a side elevational view ofa plugger member as utilized in a dental appliance embodying the invention.

Referring to the drawings in detail, reference character generally indicates a dental appliance comprising an outer housing 12 having a centrally disposed power shaft 14 extending longitudinally therein. The housing 10 is preferably molded or otherwise constructed from a suitable plastic material which may be considered as expendable or disposable, and is of substantially cylindrical configuration having one end 16 thereof open for receiving the shaft 14 therethrough. An elongated opening 18 is provided in the sidewall of the housing 12 and spaced forwardly of the open end 16 thereof. A flexible finger member 20, preferably molded integrally with the housing 12, is disposed in the proximity of the opening 18 and is normally in a raised or elevated position with respect thereto as shown in FIGS. 1 and 2. The finger 20 responds to manual pressure for flexing downwardly into and through the aperture or opening 18 in a manner and for a purpose as will be hereinafter set forth.

The forward or leading portion of the housing 12 is tapered inwardly as shown at 22, and terminates in a tubular nozzle member 24 which extends outwardly from the forward end 22 of the housing 12. The nozzle 24 preferably curved or arcuate for facilitating disposition of the outer end thereof in the proximity of a tooth cavity. The nozzle 24 is provided with a centrally disposed internal bore extending longitudinally therethrough into communication with a complementary internal passageway 28 provided in the housing conterminous with the aperture 18. The passageway 28 extends along the upper portion of the closed end 22 as shown in FIGS. 1 and 2 and is open at 29 in the proximity of the aperture 18. An aperture 30 is provided at the juncture between the passageways 26 and 28 to provide communication between the passageways and the interior of the housing 12 for a purpose as will be hereinafter set forth. In addition, an annular shoulder 32 is provided on the inner periphery of the housing 12 spaced forwardly of the aperture 18.

The shaft 14 comprises an elongated drive member 34 which extends beyond the open end 16 of the housing 12 for connection with the usual Doriot type handpiece (not shown) for rotation or actuation thereby in any well-known manner (not shown). A continuous spiral shoulder 36 is provided on the outer periphery on the shaft 34 and extends longitudinally thereon for a purpose as will be hereinafter set forth. The spiral shoulder 36 terminates at one end thereof in an enlarged rod or shaft portion 38 having an outwardly extending circumferential flange 40 spaced from the spiral member 36. A spirally disposed finger 42 extends between the outer periphery of the flange 40 and the outer periphery of the enlarged portion 38 as clearly shown in FIGS. 1 and 3. An auger shaped member or impelling element 44 extends axially outwardly from the flange 40 in the opposite direction from the enlarged portion 38. The shaft 14 is preferably molded or otherwise constructed from a suitable plastic material which is inexpensive and expendable.

A retainer cup generally indicated at46 is adapted for disposition around the shaft 14 in a manner and for a purpose as will be hereinafter set forth. The cup 46 is also preferably molded or constructed from a suitable plastic material and is substantially cylindrical have one end 48 thereof open for receiving the flange 40 therein. The opposite end is provided with a wall 49 having an aperture 50 for receiving the enlarged portion 38 of the shaft 14 therethrough. The aperture 50 is in sealing engagement with the enlarged portion 38. A reduced sleeve 52 extends rearwardly from the cup 46 and is loosely disposed around the enlarged portion 38 for receiving one end of a helical drive member 54 therein. The helical drive member 54 terminates in a plugger member 56 which extends in a reverse direction spaced from and substantially parallel with the axis of the drive member 54 as particularly shown in FIG. 5. The helical drive member 54 is disposed around the shaft 14 and particularly around the spiral shoulder portion 36 thereof as clearly shown in FIG. 1. The plugger member 56 extends forwardly of the drive portion 54 and is preferably curved complementary with the configuration of the passageway 28 for slidable insertion into the passageway 28 and reciprocation therein as will be hereinafter set forth.

During assembly of the appliance a preselected quantity of a suitable silver alloy powder (not shown) is deposited in the chamber 54 formed at the interior of the tapered end 22 of the housing 12. Of course, a suitable stopper (not shown) is inserted in the passageway 26 and extends beyond the aperture 30 for closing the aperture 30 and retaining the silver alloy powder within the chamber 54. The retainer cup 46 is inserted on the enlarged portion 38 of the shaft 14 and before disposition of the flange 40 within the open end 48 thereof a preselected quantity of mercury (not shown) is deposited within the cup 46. As hereinafter set forth, the aperture 50 is in sealing engagement with the outer periphery of the enlarged portion 38 and precludes leakage of the mercury therebetween. Subsequent to the disposition of the mercury within the retainer cup 46 the flange 40 is inserted within the open end 48 thus sealing the mercury within the retainer cup 46. The shaft 14 may then be inserted within the housing 12 and positioned therein in such a manner that the cup 46 engages the annular bore 32. The helical drive member 54 may be disposed around the spiral shoulder 36 prior to the insertion of the shaft 14 within the housing 12 and one end of the drive member 54 is preferable suitably secured within the sleeve 52 for a purpose as will be hereinafter set forth. Upon insertion of the shaft 14 within the housing 12 the plugger member 56 is inserted within the passageway 28 as shown in FIG. 1. The unit 10 then becomes a preloaded, compact, single unit for preparing silver amalgam, extruding the mixed amalgam into a tooth cavity, and selectively condensing or packing the amalgam within the cavity.

When it is desired to use the appliance 10 in connection with providing a silver filling in a tooth cavity the apparatus 10 may be connected with or secured to the dentists normal or usual Doriot type hand tool in any well-known manner. When the tool 10 is connected with the dentists Doriot type hand tool the shaft 14 is moved in a left-hand direction within the housing 12 as shown in FIG. 1 and is simultaneously rotated. The retainer cup 46 cannot move in a left-hand direction because of the engagement thereof with the shoulder 32. Thus, flange 40 is removed from the open end 48 of the cup 46 and the mercury stored within the cup 46 is free to enter the chamber 54 containing the silver alloy powder. The flange 40 and spiral finger 42 rotate simultaneously with the shaft 14 and the finger 42 assures ejection of substantially the entire quantity of mercury from the cup 46. Continued rotation of the shaft 14 rotates the auger 44 within the chamber 54 to provide a complete and thorough mixing of the silver alloy powder and mercury within the chamber 54. The

stopper (not shown) may be removed from the passageway 26 thus providing communication from the chamber 54 through the aperture 30 and through the passageway 26 to the exterior of the nozzle 24. Continued rotation of the shaft 14 causes the auger 44 to extrude the silver alloy-mercury or amalgam mixture into the passageway 26.

The plugger 56 inserted within the passageway 28 is also deposited in substantial alignment with the flexible finger of the housing 12. When the dentist desires to inject or insert a quantity of the amalgam into a tooth cavity he may manually press or squeeze the finger 20 against the plugger member 56. This squeezing action or pressure against the plugger 56 contracts the helical drive member 54 radially inwardly into engagement with the spiral shoulder 36. This engagement of the helical member 54 with the spiral shoulder 36 causes 'the drive member 54 to move or coil up in a direction toward the cup 46 by virtue of the longitudinal contraction of the helical configuration of the drive member 54. As the drive member contracts or moves toward the cup 46 the plugger 56 is moved in a left-hand direction as shown in FIG. 1 through the passageways 28 and 26 for extruding or ejecting the amalgam from the passageway 26. Of course, the nozzle 24 is disposed in a proximity of the tooth cavity whereby the extruded or ejected amalgam will be deposited within the cavity.

The rotation of the shaft 14 may be controlled by proper manipulation of the Doriot handpiece as is well known when it is desired to use the tool 10 for condensing or packing the amalgam in the cavity. AI- ternate releasing of and application of pressure on the finger 20 will reciprocate the plugger 56 within the passageways 28 and 26 selectively at the control of the dentist or operator of the tool 10. The plugger 56 extends beyond the open end of the passageway 26 in the fully contracted position of the drive member 54 and may be utilized for packing or condensing the load of amalgam which has been placed within the tooth cavity prior to the insertion of an additional quantity into the tooth cavity. The operatio of injecting the amalgam into the tooth cavity and packing of the amalgam may be repeated until the tooth cavity has been properly or adequately filled with silver amalgam. Subsequent to the filling of the tooth, the upper portion or surface of the filling may be carved or prepared in the usual manner for completing the tooth filling and the expended tool or appliance 10 may be discarded.

Whereas the particular embodiment depicted herein is adapted for use with the usual Doriot type handpiece, it is to be understood that the unit 10 may be an independently operated unit in that a permanent power source may be provided for the unit, if desired. In this instance, the power source would be considered as a permanent or lasting tool whereas the functional portions of the unit which prepare, place and pack the amalgam will be disposable as hereinbefore set forth.

It is to be noted that the curved configuration of the nozzle 24 is particularly selected for ease of accessibility to substantially any tooth in the mouth, and to substantially any size, shape or location of the tooth cavity. Of course, there are a few locations in the mouth wherein the cavity may not be accessible, but these locations would not be more than one to two per cent of any cavities normally found in tooth problems. in addition, it is to be noted that whereas the particular mixing element for the silver alloy and mercury as depicted herein is an auger type device, there is no intention of limiting the mixing operation to this type of mixing action. A centrifugal type mixing, or any other type of mixing action may be provided for the tool 10. Furthermore, it is anticipated that a plurality of plugger sizes may be provided for the unit 10 to assure a versatility of use for substantially any silver filling operation for a tooth cavity.

From the foregoing it will be apparent that the present invention provides a novel method and means for filling tooth cavities with a silver amalgam. The novel appliance is preloaded with the proper ratio of silver alloy powder and mercury, with the ingredients maintained in separate compartments until the amaigam mixture is required for use. The ingredients are thoroughly and efficiently mixed within the appliance, and extruded through a nozzle directly into the tooth cavity. A plugger is provided in the tool for selectively packing or condensing the amalgam in the cavity as desired by the dentist. Subsequent to the tooth filling operation, the appliance may be discarded. Thus, the entire process of preparing silver amalgam and placing the amalgam in a tooth cavity is greatly simplified, with a reduction on the manual handling of tools between the dentist and the dental assistant, and elimination of amalgam mixing devices. In addition, the mixed amalgam is maintained fresh during the entire tooth filling operation, thus improving the overall results.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it

should be understood that other and further modifications, apart from those shown or suggested herein, may

by the drive shaft means and operable thereby for cooperation with the nozzle means to extrude said mixed amalgam from the nozzle for insertion within the tooth cavity, means carried by the housing for cooperation with the plugger means for selective reciprocation of the plugger means for packing of the amalgam mixture within the tooth cavity, and wherein the drive shaft is rotatable within the housing and comprises means for separating the interior of the housing into two sealed chambers for housing the preloaded ingredients of the amalgam, said shaft being selectively operable for combining the ingredients within one of said chambers whereby said mixing means mixes the ingredients therein.

2. A disposable dental appliance as set forth in claim 1 wherein the drive shaft is provided with spiral shoulder means for cooperating with the plugger means for reciprocation thereof. l

3. A isposable dental appliance as set forth in claim 2 wherein flexible finger means is provided on the housing for cooperation with the plugger means and spiral shoulder means for selective reciprocation of said plugger means.

4. A disposable dental appliance as set forth in claim 7 3 wherein the plugger means includes a spiral portion disposed around the drive shaft engageable by the finger means and radially contractable for engagement with spiral shoulder means to provide said reciprocation for said plugger means. 7

5. A disposable dental appliance for filling tooth cavities with silver amalgam which comprises a housing, a drive shaft extending longitudinally within the housing and rotatably disposed therein, said drive shaft being rotatable by an external and separate power source, a first chamber provided in the housing and having a preloaded quantity of silver alloy powder therein, a second chamber provided in the housing and having a preloaded quantity of mercury therein, means for sealing the second chamber from the first chamber prior to mixing of the ingredients, mixing meanscarried by the drive shaft and disposed in one of said chambers,

nozzle means provided on the housing, passageway means providing communication between the interior of the housing and the exterior of the nozzle means,

plugger means carried by the drive shaft and extending reciprocally into the passageway means, means cooperating between the drive shaft and the housing for selective reciprocation of the plugger means, means carried by the drive shaft for combining the ingredients in one of said chambers upon rotation of the drive shaft by the external power source whereby the ingredients are mixed by said mixing means and moved into said passageway for extrusion therefrom by said plugger means. 

1. A disposable dental appliance for filling tooth cavities with silver amalgam which comprises housing means having the ingredients of the silver amalgam separately preloaded therein, drive shaft means extending longitudinally within the housing means, mixing means carried by the drive shaft means and operable thereby for mixing the amalgam ingredients, nozzle means carried by the housing means and in communication with the interior thereof, plugger means carried by the drive shaft means and operable thereby for cooperation with the nozzle means to extrude said mixed amalgam from the nozzle for insertion within the tooth cavity, means carried by the housing for cooperation with the plugger means for selectiVe reciprocation of the plugger means for packing of the amalgam mixture within the tooth cavity, and wherein the drive shaft is rotatable within the housing and comprises means for separating the interior of the housing into two sealed chambers for housing the preloaded ingredients of the amalgam, said shaft being selectively operable for combining the ingredients within one of said chambers whereby said mixing means mixes the ingredients therein.
 1. A disposable dental appliance for filling tooth cavities with silver amalgam which comprises housing means having the ingredients of the silver amalgam separately preloaded therein, drive shaft means extending longitudinally within the housing means, mixing means carried by the drive shaft means and operable thereby for mixing the amalgam ingredients, nozzle means carried by the housing means and in communication with the interior thereof, plugger means carried by the drive shaft means and operable thereby for cooperation with the nozzle means to extrude said mixed amalgam from the nozzle for insertion within the tooth cavity, means carried by the housing for cooperation with the plugger means for selectiVe reciprocation of the plugger means for packing of the amalgam mixture within the tooth cavity, and wherein the drive shaft is rotatable within the housing and comprises means for separating the interior of the housing into two sealed chambers for housing the preloaded ingredients of the amalgam, said shaft being selectively operable for combining the ingredients within one of said chambers whereby said mixing means mixes the ingredients therein.
 2. A disposable dental appliance as set forth in claim 1 wherein the drive shaft is provided with spiral shoulder means for cooperating with the plugger means for reciprocation thereof.
 3. A disposable dental appliance as set forth in claim 2 wherein flexible finger means is provided on the housing for cooperation with the plugger means and spiral shoulder means for selective reciprocation of said plugger means.
 4. A disposable dental appliance as set forth in claim 3 wherein the plugger means includes a spiral portion disposed around the drive shaft engageable by the finger means and radially contractable for engagement with spiral shoulder means to provide said reciprocation for said plugger means. 